Casing perforator



July 7, R s. SMH-H v CASING .PRFORATOR Filed April 27, 1936 2Sheets-Sheet l July 1, 1936. R s. SMITH 2,046,752

CASING PERFORATOR Filed April 27, 1936 2 Sheets-Sheet 2 j] v l 15; 4Z JZPatented July 7, 11936 UNITED ySTATES PATENT FFICE CASING PERFORATOR ofCalifornia Application April 27, 1936, Serial No. 76,567

V8 Claims.

This invention has tof'do in a general way with perforators for wellcasing'and is more particularly related to imp-rovements in aperforato-r of the general type shown and described in United StatesLetters Patent No. '1,6l5i'1'72, issued to D. W. Hoferer on January 18th,1927.

As is well kknown to thoselfamiliar Vwith theart, perforators of thisgeneral character are designed for use in penetratingcrperforatingoilwell casing after it has been installed in a well, and the generalconstruction-followed in such perforators involves the use of a bodymember which carries a knife or cutter associated with Ameans forvadvancing or swinging the-'sameoutwardly from thebody into engagementwith the casing wall to be perforated. In order that the perforator maybe lowered. into the casing without interference it is necessarythat-the knife or cutter be mounted so as to'normally -becontainedwithin the body'and since it ris desirable that the knife reach as farasfpossible throughthe Wall of the casing when lit is extended, suchknife must have a. considerable length. These factors intro duce severalproblems intothe design of a perforator of this character,-chiefVof'vvhich involves themeans for swinging the knife from the bodyinamanner such that it'will bite into Ithe wall of the casing so as to Vbedriven through such vwall by 4a downward driving force on the body. y

In the Hoferer perforator'referred to above, this is accomplishedbyempleying a doublevedged knife having one Vshort'point'and vonelongpoint, the short point being adapted to liniti'allyie'ngage thecasing wall, the intention ofsuch'en'gagement being to Voffer sufoientresistance'to the movement of the knife to cause the'sam'e to swing-intoa position a-t `which the long blade will -perforate the casing. Inactual practiceghowever, I 4have discovered that with the Hoferer designthe short blade has a greater tendency to skid along the casing duringthe downward driving force on the body so that it is at most merelyeffective to marcel or groove the casing metal.

It therefore becomes a primary object of vthis invention to providemeans which are particularly adapted for use in y-a -perforator of theHoferer type which will positively support the cutter during downwardmovement of the body and-through such support force the same into thewall lof the casing a sufficient distancelto insure the completepenetration lof the casing -as the body is subjected to further jarringor driving action.

After the'blade has penetrated vthe casing in the manner `just referredAto above, itis important that the body be capable of receiving furtherdownward movement in order that the cutter may be fully extended andalso permit the elongation of the perforation if this is desired.

It is, therefore, a further object of this invention to provide a cuttersupporting member of the class just referred to which, after it has heldthe cutter against the casing under driving action on the body over asufficient period to force the cutter well into or through the casing,will under continued driving force permit downward movement of the bodyand will itself move down- Wardly with respect to the casing.

The improvement contemplated by this invention embodies what I may terma tongue member which is slidably and pivotally mounted in the bottomvportion of the groove which carries the cutter at its upper end, suchtongue member being associated with anchor means/for swinging same fromthe body.

It is a further object of this invention to prol' vide means forautomatically and positively withdrawing the to-ngue back into the bodygroove when the body is raised, thereby permitting the blade or cutterto fall freely back into the groove vand also removing any projectionswhich might catch on a projecting shoulder in the cas-ing during thewithdrawal of the tool.

The details in the construction of a preferred form of my invention,together with other objects u attending its production will be bestunderstood from the following description of the accompany ing drawingswhi-ch are chosen for illustrative purposes only and in which Fig. 1 isan elevational view showing a preferred'form of perforator equipped withmy invention;

Fig. 2 is .an enlarged fragmentary sectional elevation taken in a planerepresented by the line 2 2 of Fig. l, and illustrates the parts in theposition which they occupy while the tool is being withdrawn from thewell; Y

Fig. 3 is an enlarged fragmentary sectional elevation similar to Fig. 2,but illustrating the parts arranged in the positions which they occupyat the start of a perforating operation;

Fig. 4 is a fragmentary sectional yelevation taken in a planerepresented by the line 4 4 of Fig. 2;

Fig. 5 is a sectional elevation taken in a plane represented by the line5-5 of Fig. 2;

Fig. 6 is a plan section on the line 6 6 ofv Fig. 2;

Fig.'7 is a plan section on the line 1 1 of Fig. 2;

Fig. 8 is a plan section on the line 8 8 of Fig. 2; 'and Fig. 9 is aplan section on the line 9-9 of Fig. 2. More particularly describing theinvention as herein illustrated, reference numeral II indicates aperforator body equipped at its upper end with a sub II whereby it maybe attached to suitable suspending and driving means such as a jar, notshown. The body II is shown as being provided with a longitudinal grooveI2, the side faces of such groove being milled out as indicated atI3--I3 to admit the reception of bosses I4 on a cutter member generallyindicated by reference numeral I5. The bosses I4 on the cutter memberare received in the inner offset ends I3 of the milled out slot I3-I3and are held in place therein through the medium of retaining platesindicated at I6.

As best illustrated in Fig. 2, the cutter I5 is pivoted in the rearportion and at the upper end of the groove I2. This cutter, like thecutter of the Hoferer patent above referred to is shown as having a longblade I8 and a short point I9. The short point I9 of this cutter,however, is not intended to have any substantial biting action on thecasing, its function in holding the blade being merely secondary in viewof the improved blade supporting means contemplated by this invention.As will be observed from Figs. 2 and 3, the upper end of the slot I2above the cutter is provided with an inclined face 29 which is engagedby the cutter when it is in its fully extended position shown in brokenlines in Fig. 2. This inclined face may be formed during the milling ofthe groove or it may be provided by the insertion of a block 2I which isshown as being held in place by means of a pin 22.

The portion I2' of the groove I2 which extends downwardly below theregion of the cutter I9 is shown as being widened so as to provide ashoulder 25 on the upper end of the section I2' of the groove. On thetwo side faces of this widened portion I2 near its lower end, I providealigned channels 2B which communicate with the outer face of the groovethrough slots 2I. These channels 26 receive the ends of a cross pin 29which is mounted on the lower end of what I may term a tongue member 39,such tongue member being, through the medium of the pin 29, slidably andpivotally supported in the groove section I2. The upper end of thetongue member 39 is provided with a, downwardly inclined shoulder 3| andthe outer face of this member below the upper edge of the shoulder 3I isformed with a recess 32 within which a serrated wheel 33 is mounted upona pivot pin 34. The rear portion of the tongue member 39 is shown asbeing cutaway as indicated at 49 such cut-away portion including agroove section 4I shaped so as to provide an inclined face 4I.

It will be understood that, in the operation of this tool, operativeeffect is given to the cutter by downward jarring movement applied tothe body and the purpose of the tongue member as pointed out above is toprovide a supporting surface which may be positively wedged against thecasing with suicient force to swing the cutter I8 downwardly intoengagement with the casing and to support such cutter during thisengagement so that the cutter is positively driven through the wall ofthe casing by downward jarring action on the body.

The wedging action of the tongue member referred to above isaccomplished through the medium of a shoe member 45 which has aninclined or wedged shaped face 46 adapted to engage the face 4I on thetongue 39. This shoe 45 is mounted on the upper end of a mandrel 49which slidably extends through a passage 59 in a block 5I, such blockbeing secured in the bottom of the groove by means of cross pins 5I Thismandrel 49 carries at its lower end a friction tail piece of anyconventional type indicated by reference numeral 52.

For purposes of illustration, the tail piece 52 is shown herein ascomprising an elongated sleeve section 53 having a shoulder 54 in itsupper end adapted to be engaged by a head 55 on the bottom of themandrel. Mounted on the sleeve 53 at a substantial distance below theshoulder 54 is a collar 51 to which a plurality of flexible springmembers 58 are secured at their upper ends, the lower ends of suchspring members being received in another collar 59 which is mounted onthe bottom of the sleeve 53. In order that the tail piece 58 may beutilized to support the mandrel 59 against downward movement, andthereby constitute such mandrel an anchor member, which will remainstationary during further downward movement of the body, it is necessaryto provide a latch of some conventional type whereby the tail piece andthe mandrel can be 2 locked against collapsing movement relative to eachother. A preferred form of such latch is shown as comprising a fingermember 6I pivoted to the collar 5l as indicated at 62 and adapted toswing through slots 63--64 in the upper end of i the sleeve 53. Thisnger member 6I is associated with a leaf spring 65 secured to the sleevenut 54 by means of a screw 66, the spring being effective to bias thetongue inwardly toward its horizontal position.

In the operation of the perforator contemplated by this invention, theleaf spring assembly and the mandrel are drawn to their fully extendedpositions, the finger 6I is raised to its vertical position and ispressed outwardly against the action of the spring 65 after which thespring assembly is moved upwardly on the mandrel so as to assume theposition shown in Fig. 1. The spring assembly is then inserted into thecasing its resistance therein being sufficient to hold the same againstthe body as shown in Fig. l and the weight of the mandrel at the sametime is sulcient to hold it in its lowermost position as illustrated inFig. 2. In this position it will be observed that the lower end of theshoe 45 engages a shoulder 68 formed in the bottom of the groove 49 onthe tongue and through such engagement holds the tongue in its retractedposition.

The weight of the cutter and the manner in r which it is pivotedmaintains the cutter in retracted position so that it is entirelyenclosed within the groove of the body. When the perforator arranged inthis manner has been lowered into the well to the point at which it isdesired to l comes into engagement with the face 46 on the shoe. Thetongue is thereby supported against further downward movement relativeto the body such movement of the body taking place by virtue *garajes ofthe pin and slot connection 29-26. As this downward movement of the bodycontinues the lower edge of the blade I8 comes in contact with theshoulder 3 I. As movement is'continued from this point, the wedgingaction between the faces 4l and 46 on the tongue and the shoerespectively cause the tongue to swing outwardly from the body bringingthe sharp corners on the serrated wheel 33 into engagement with the wallof the casing. The cutter l5 also swings outwardly during this movementso that the short point I9 also engages the casing. Due to the wedgingaction between the faces lll-46 further jarring action on the bodycauses the sharp corner on the wheel 33 to bite into the wall of thecasing providing a stationary member against which the long point 8 ofthe knife is driven. This stationary unit forces the knife from theposition shown in full lines in Fig. 3 into the position shown in brokenlines in Fig. 3 where it will be observed that the blade has been forcedthrough the wall of the casing.

When this position has been reached, in the form of my invention shownherein, the shoulder 2.5 has been lowered into engagement with theshoulder 3| on the tongue and the blade has penetrated the casing asuiiicient distance to be carried on to its fully extended position bycontinued downward driving actionon the body. It is important,therefore, that the holding means associated with the tongue be of anature such as to permit further downward movement of the body underthis continued driving action and this is accomplished through the useof a serrated wheel which will, under such continued driving action tendto rotate as contrasted with a positive gripping member such as a slip.In this connection, it will be observed that up until such time as theshoulder 25 engages the top of the tongue, there is no direct drivingforcefapplied to the tongue. The serrated wheel being wedged into thewall of the casing where the force required to cause it rto rotate mustbe greater than the force necessary to swing the blade through thecasing. rIhe downward driving force up to this point, therefore, iseffective to bring the fulcrum of the blade down toward the top of thetongue.

When the perforation has been completed and it is desired to raise theperforator either to effect a perforation at a higher point or withdrawit from the well, it will be observed that when lifting force is appliedto the body the shoe 48 will be held against movement through frictionalengagement of the springs 58 with the wall of the casing, such springsacting upon the shoe through the medium of the mandrel and the head 55.With this arrangement as the body raises the tongue to a point at whichthe shoulder 68 engages the underside of the shoe, such engagement willautomatically snap the tongue back into its vertical position where itis entirely enclosed within the groove thereby removing any projectedsurfaces which might cause the perforator to be held up by shoulderswithin the casing.

It is to be understood that while I have herein described andillustrated one preferred form of my invention that the invention is notlimited to the precise construction described above, but includes withinits scope whatever changes fairly come within the spirit of the appendedclaims.

I claim as my invention:

l. In a casing perforator having a longitudinally grooved body with acutter pivotally mounted in the upper end of said groove, means forswinging said cutter from said groove into engagementv withv a casingand maintaining such engagement during an initial downward movement ofsaid body comprising: a tongue member slidably and pivotally mounted inthe bottom portion of said groove; a'shoe slidably mounted in saidgroove behind said tongue and adapted to simultaneously support saidtongue against downward movement and swing the same outwardly from saidbody during downward movement of said body relative to said shoe; meanson said tongue for'biting into a casing whenY the tongue is forcedoutwardly by said shoe; and a shoulder on the top of said tongue forforcing said cutter into the wall Vof a casing during downward movementof said body relative to said tongue.

2. In a casing perforator having a longitudinally grooved body with acutter pivotally mount-- ed in the upper end of said groove, means forswinging said cutter from said groove into engagement with a casing'andmaintaining such engagement during an initial downward movement of saidbody comprising: a tongue member slidably and pivotally mounted in thebottom portion of said groove; a shoe slidably mounted in said groovebehind said tongue and adapted to simultaneously support said tongueagainst downward movement and swing the same outwardly from said bodyduring downward movement of said body relative to said shoe; meanscomprising a serrated wheel mounted in said tongue and projectingoutwardly therefrom, for biting into a casing when the tongue is forcedoutwardly by said shoe; and a shoulder on the top of said tongue forforcing said cutter into the wall of a casing during downward movementof said body relative to said tongue.

3. In acasing perforator having a longitudinallygrooved body with acutter p-ivotally mounted in the lupper lendof said groove, means forswinging said cutter from said groove into engagement with a casing andmaintaining such engagement during an initial downward movement of saidbody comprising: la tongue member slidably and pivotally mounted in thebottom portion of said groove; a shoe slidably mounted in said groovebehind said tongue and adapted to simultaneously support said tongueagainst downward movement and swing the same outwardly from said bodyduring downward movement of said body relative to said shoe; means onsaid tongue for biting into a casing when the tongue is forced outwardlyby said shoe; a shoulder on the top of said tongue for forcing saidcutter into the wall of a casing during downward movement of said bodyrelative to said tongue and means at the bottom of said tongue adaptedto be engaged by said shoe in its lowermost position for holding saidtongue in a retracted position.

4. In combination with a casing perforator having a longitudinallygrooved body and a cutter pivotally mounted in the upper end of thegroove therein, means for swinging said cutter into the wall of a casingduring downward movement of said body comprising: a tongue memberslidably and pivotally mounted in the bottom portion of said groove; ashoe slidably mounted in said groove behind said tongue, said shoe andtongue having faces adapted for wedging engagement upon downwardmovement of said tongue relative to said shoe whereby said tongue isswung outwardly from said body; means on said tongue for biting into acasing when said wedging faces are in engagement; friction meansassociated with said shoe and engageable with a casing to hold said shoeagainst downward movement; and a shoulder on the upper end of saidtongue adapted to be engaged by said cutter for swinging said cutterduring downward movement of said body relative to said tongue.

5. In combination with a casing perforator having a longitudinallygrooved body and. a cutter pivotally mounted in the upper end of thegroove therein, means for swinging said cutter into the wall of a casingduring downward movement of said body comprising: a tongue memberslidably and swingably mounted in the bottom portion of said groove;casing gripping means mounted near the upper end of said tongue; ashoulder on said tongue engageable with said cutter for swinging saidcutter from said body during downward movement of said body relative tosaid tongue; and means including an anchor Vmember slidably supported bysaid body and engageable with a casing for simultaneously supportingsaid tongue against downward movement and swinging same from saidgroove.

6. In combination with a casing perforator having a longitudinallygrooved body and a cutter pivotally mounted in the upper end of thegroove therein, means for swinging said cutter into the wall of a casingduring downward movement of said body comprising: a tongue memberslidably and swingably mounted in the bottom portion of said groove; aserrated wheel rotatably mounted in said tongue near the upper endthereof with a portion projecting therefrom for biting into the wall ofa casing when said tongue is swung from said body; a shoulder on saidtongue engageable with said cutter for swinging said cutter from saidbody during downward movement of said body relative to said tongue; andmeans including an anchor member slidably supported by said body andengageable with a casing for simultaneously supporting said tongueagainst downward movement and swinging same from said groove.

'7. In combination with a casing perforator having a longitudinallygrooved body and a cutter pivotally mounted in the upper end of thegroove therein, means for swinging said cutter into the wall of a casingduring downward movement of said body comprising: a tongue memberslidably and swingably mounted in the bottom portion of said groove;casing gripping means mounted near the upper end of said tongue; ashoulder on said tongue engageable with said cutter for swinging saidcutter from said body during downward movement of said body relative tosaid tongue; and means including an anchor member slidably supported bysaid body and engageable with a casing for simultaneously supportingsaid tongue against downward movement and swinging same from said groovesaid last mentioned means including a wedging shoe slidably mounted insaid groove behind said tongue.

8. In combination with a casing perforator having a longitudinallygrooved body and a cutter pivotally mounted in the upper end of thegroove therein; means for swinging said cutter into the wall of a casingduring downward movement of said body comprising: a tongue membershdably and swingably mounted in the bottom portion of said groove;casing gripping means mounted near the upper end of said tongue; ashoulder on said tongue engageable with said cutter for swinging saidcutter from said body during downward movement of said body relative tosaid tongue; and means including an anchor member slidably supported bysaid body and engageable with a casing for simultaneously supportingsaid tongue against downward movement and swinging same from said groovesaid last mentioned means including a shoe member slidably mounted insaid groove behind said tongue, and said tongue having a shoulder at itslower end adapted to be engaged by said shoe upon upward movement ofsaid body relative to said anchor member for withdrawing said tongueinto said groove.

ROBERT S. SMITH.

